Many plants are first grown in nursery beds rather than planted directly. These are then removed from the beds and transplanted into field or forest land where the plants mature. One concern is that the plants' roots and stems are relatively undamaged when they are lifted from the nursery beds. Otherwise, root loss or stem damage can have an adverse effect on plant development.
A number of harvesting apparatuses are available for harvesting or lifting plants that are subsequently to be transplanted. Some harvesting apparatuses can include plant conveyors. Some current conveyors include paired belts on a rail and pulley system mounted rigidly to a harvester frame. These paired belts grasp and move plants up and away from nursery beds. Then, the paired belts release the plants into a storage bin wherein they are gathered or stacked.
The gap between each pair of belts can be kept at a distance wide enough for the plants to travel up the belts without stem damage but close enough so that the plants do not slip from the paired belt and drop to the ground. In existing systems, the gap between each pair of belts of current conveyors can only be adjusted mechanically by loosening bolts attaching the belt rails to the harvester frame and physically moving the rails closer together or farther apart.